Propulsion Short
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Propulsion Short
On November 29, 2009, in New York City, in age of 95 passed away Arthur Kantrowitz. Kantrowitz will be always remembered among most prominent American scientists of past century as a founder of Avco Everett Research Labs, professor of Dartmouth College, holder of numerous patents (from medicine to space) and supporter of Science Court. However, in this short note I would like to say a few words about one of his greatest contributions, which he made for us all and for future generations: the founding of laser propulsion.
Laser Propulsion is a part of rocket science, but don’t be discouraged by a silly tag: the idea is simple. We pay on average $10,000 per every pound of payload delivered to low earth orbit. Why that much? Because, we use very inefficient carriers: chemical rockets. These hydrogen gluttons have to carry everything onboard: fuel, oxidizer, cryogenics, tanks, lines, you name it, leaving a small (and very expensive room) for the payload. If we could only find a way to separate the energy source from the vehicle, deliver that energy to the vehicle from some power station, the gain in efficiency of such vehicle will be tremendous.
The energy can be delivered with powerful laser beams! Believe it or not, the original idea was published in 1924 by Konstantin Tsiolkovsky, the space scientist and great visionary, who preceded his own times for at least on half-century. Tsiolkovsky pointed out that energy can be delivered to a space rocket by means of tight light beams (first laser was built 35 years later). The idea of light-beaming energy to a rocket that could be just a dream in 1924, was refined, formulated and delivered by Arthur Kantrowitz as a precise scientific concept of laser propulsion.
In 1972 Arthur Kantrowitz published in Astronautics and Aeronautics “Propulsion to Orbit by Ground Based Lasers”, a scientific paper which started a new field: laser propulsion. In this paper Kantrowitz proposed to change our very approach to space launches: instead of building larger (and even less energy-efficient rockets), start using high-power lasers for space launches of small satellites. Such satellites would literally straddle the tip of laser beam, focused on their “propellant” area. When high power laser beam is focused (even loosely) on a solid matter, such matter is evaporated and ionized almost instantaneously, i.e. the release of energy is much higher than one used from burning hydrogen in rockets. So, laser-driven vehicle will be still flying on the same rocket principle, but exhaust energy and structural lightness will be incomparably superior to hydrogen-burning rockets.
Driven by laser rocket will be composed of very light focusing mirrors, relatively small (energy efficient) solid propellant and, voila: the rest will be payload! Forget heavy liquefied gases (oxygen and hydrogen), cryogenics, fuel tanks and lines, combustion chambers, etc.: Payload, Propellant and Photons, Period! Arthur Kantrowitz called it 4P Rule. Bottom line: scientifically sound calculations have shown that the price of one pound of a payload delivered to low earth orbit will be drop to $100. Laser propulsion offers 100-fold, revolutionary savings on space deliveries.
The original paper of Kantrowitz was like a first milestone at the beginning of a long way, a scientific quest for beamed-energy propulsion. Kantrowitz not mere wrote a fundamental paper, he started the first in the world research program on laser propulsion at Avco Everett Research Labs. Decade later new research projects followed the cause and two decades later first laser-driven vehicles were launched into air (but not to space yet). New countries: Russia, Japan, Germany, China opened their own research programs and hundreds of researchers joined the field. New forms for beamed-energy propulsion were found, such as microwave propulsion. Hundreds of people work on this field today, the work is in progress, there is still a lot to do. Remarkably, this field was opened by one man, Arthur Kantrowitz, and he will be always remembered for that.
About the Author:
Andrew Pakhomov is founder and president of American Institute of Beamed Energy Propulsion, a nonprofit scientific organization serving to development and popularization of this space technology of the future AIBEP He is also associate professor of physics at University of Alabama in Huntsville. To read more about Arthur Kantrowitz and fascinating field of laser propulsion, please visit official site of AIBEP.
Article Source: ArticlesBase.com - Arthur Kantrowitz, Founder of Laser Propulsion